-- Script calculates average length of queries at each hour of the day

raw = LOAD 'data/excite-small.log' USING PigStorage('\t') AS (user:chararray, time:chararray, query:chararray);

houred = FOREACH raw GENERATE user, baconsnake.ExtractHour(time) as hour, query;

hour_group = GROUP houred BY hour;

hour_frequency = FOREACH hour_group GENERATE group as hour, baconsnake.AvgLength($1.query) as count;

DUMP hour_frequency;

-- The excite query log timestamp format is YYMMDDHHMMSS
-- This function extracts the hour, HH
def ExtractHour(timestamp):
	return timestamp[6:8]

-- Returns average length of query in a bag
def AvgLength(grp):
	sum = 0
	for item in grp:
		if len(item) > 0:
			sum = sum + len(item[0])	
	return str(sum / len(grp))
